Define 'lipid bilayer'.
A thin polar membrane made of two layers of lipid molecules; these membranes are flat sheets that form a continuous barrier around cells
Define a carbohydrate's basic molecular formula.
CH2O (carbon, hydrogen, oxygen in a two-to-one hydrogen to oxygen ratio)
Define 'apoptosis' and its significance in multicellular organisms.
Programmed cell death, crucial for development and maintaining cell populations
Define 'mutation' in genetics.
A change in the DNA sequence
Define 'metabolism'.
All chemical reactions that occur in living organisms to maintain life
Define 'genetic code'.
The set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins by living cells
Define 'allosteric regulation' in enzymes.
Regulation of an enzyme's activity through binding of a molecule at a site other than the enzyme's active site
Define the primary structure of proteins.
Linear sequence of amino acids in a polypeptide chain
Define anabolism and catabolism.
Anabolism is the synthesis of complex molecules; catabolism is the breakdown of complex molecules.
Define oxidative stress and its impact on cells.
Imbalance between free radicals and antioxidants, leading to cell damage
Define 'ecosystem'.
A biological community interacting with its environment
Define tertiary structure of a protein.
Three-dimensional folding pattern of a protein due to side chain interactions
Define the structure of an alpha helix.
A right-handed coil or spiral conformation of amino acids in proteins, stabilized by hydrogen bonding
Define 'denaturation' of proteins.
A structural change in proteins that results in the loss of their biological properties, typically caused by heat or chemicals
Define the role of chlorophyll in photosynthesis.
Absorbs light energy to convert carbon dioxide and water into glucose and oxygen
Define 'polypeptide'.
A long chain of amino acids
Define the role of neurotransmitters in the nervous system.
Chemical messengers that transmit signals across a synapse from one neuron to another
Define 'active transport' in cell biology.
Movement of molecules across a membrane requiring energy
Define 'monosaccharide' with an example.
Simplest form of carbohydrates, e.g., glucose
Define secondary structure of proteins.
Alpha helices and beta sheets formed by hydrogen bonding
Define the quaternary structure of proteins.
The assembly of multiple polypeptide chains into a functional protein complex
Define the structure and function of microtubules.
Cylindrical tubes of tubulin that provide structural support and play a role in cell division and intracellular transport
Define 'lipids' and list two functions.
A group of naturally occurring molecules that include fats, waxes, sterols; functions include energy storage and forming cell membranes
Define gluconeogenesis.
The synthesis of glucose from non-carbohydrate sources
Define a phospholipid and its role in cells.
A lipid containing a phosphate group; forms the primary structure of cell membranes